Cranked axle

I've been looking at the steam engine paintings by Henry Maurice Whitcombe

bbc.co.uk/arts/yourpaintings/paintings/search/painted_by/henry-maurice-whitcombe

A number of them have two driving wheels with inboard cylinders. (first photo)

Would I be right in thinking that the pistons are connected to a cranked driving axle.

The second photo has what appears to be inboard cylinders but an outboard connecting rod.

The third photo is just a novel French engine this cylinders half way along the frames

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Eric,

Nothing unusual about inside cylinders/pistons driving a cranked axle. A very large number of locos had this arrangement. It is not possible to have inside coupling rods.

Correct terminology; a connecting rod connects the crank (inside or outside) to the cross head. The wheels are connected together by coupling rods that for obvious reasons can never be inside the wheels.

Eric

Yes 1 & 2 are inside cylindered locos, not an uncommon arrangment even in later days, but not easy for the maintenance crews!

No 2 must have a cranked layshaft where you might expect to find another axle!

2 and 3 appear to be a Cramptons - by a British designer Robert Crampton, if built in France.

Neil

Yes, No 2 is a Crampton buil in 1851 by Robert Stephenson company for the South Eastern Railway.

Hello Chaps---------- yes, No2. has a JACKSHAFT drive.... Take a look at this }-------------- http://en.wikipedia.org/wiki/Jackshaft_(locomotive) ------------- No3. is the image that most would associate with the name Crampton I think ??

Hi Alan,

The jackshaft design was Crampton's solution to inside cylinders driving wheels behind the firebox, so just as much a 'Crampton' as "No. 3" .

What a shame we can't see these curious beasties in action.

Neil

An earlier post suggested that coupling rods cannot be inside the wheels. Not so. Chapelon in his 2-10-0 compounds used inside coupling rods (between the frames and hence 'inside the wheels' ) to couple the H.P. and L.P. cylinders. This arrangement is clearly shewn in the reprint of Chapelon's book "La locomotive a' vapeur" figure 319

Sorry - but before anyone else spots the mistake- I meant 2-10-2